Interesting factoid (for those outside the Pacific NW) but the Seattle area is the least air conditioned major metro area, since I was young we’ve relied on fans bringing in cold air at night and room/window AC units the past decade. However the past few summer wildfires have seriously put a damper on the fans solution and the recent heat bubble pushed things over the edge. 

Of course AC isn’t great environmentally – it increases power consumption which in many cases means significant powerplant emissions and the refrigerants can be very powerful greenhouse gases if you have a leak. 

So instead I got a heat pump which is basically an AC with a reversing valve and all the same downsides of AC. I know that sounds bad, but hear me out for a second. The cool thing about a heat pump is it can generate heating and cooling – meaning that instead of burning natural gas in my furnace which emits 11.7lbs of CO2 per therm I can generate most of the home’s heat with zero emissions electricity. 

Note I said most of the home’s heat, for a few reasons I kept the existing high efficiency gas furnace. First off you need to know heat pumps come in a variety of types such as single stage, dual stage, and variable speed. I purchased a single stage unit which will efficiently heat the house when the outside temperature is at least 40 degrees, then the gas furnace will kick in. A cold climate variable speed heat pump would be able to heat my house in any Seattle weather but at significantly higher equipment cost than a single stage unit like I got. Variable speed is also more efficient, but looking at equipment cost vs operating cost savings it didn’t make a lot of sense in my case. 

The other issue is backup heat, we get a lot of power outages in my neighborhood and backing up a heat pump takes a large generator – so no matter what I’m not getting rid of fossil fuels entirely. On the other hand backing up a gas furnace has modest power requirements, we run that off an inverter connected to an EV. 

So in the end I didn’t completely eliminate the heating emissions, but I made a cost effective major reduction in emissions while getting some much needed cooling. I think that’s a good trade-off because that money can be used elsewhere for more significant emissions reductions. 

In case you wonder what my heat pump costs to run, so far I’m seeing a daily cost when it runs (which isn’t every day) of about 50¢ to $1.50 for the heat pump. In other terms, cooling in the PNW is pretty cheap. At the time I can’t yet compare to the gas furnace for heating, but later this winter I’ll have an update.

As for some heat pump shopping tips:

• I suggest ensuring you get an Energy Star unit. Note Energy Star units also have $300 federal rebates which you may be eligible for. Also check with your utility for local rebates. 
• My hope is a higher quality unit will be less likely to break and leak refrigerants. I got an American Standard which was top rated by Consumer Reports. Also expect annual maintenance on the heat pump to ensure it’s in good condition. 
• I went with Arden Heating & Cooling after getting a referral from a neighbor and getting five quotes. I’d highly recommend them to anyone in the Seattle/Metro area.